In a typical progressive press forming operation a sheet or strip of metal is advanced through successive stages of a die and a desired final product shape is imparted to the metal in progressive stages. The metal is advanced between the stages whilst the die components are open and press forming of the metal is effected in each stage during each closing stroke. U.S. Pat. No. 4,309,889 discloses a typical progressive press forming operation.
A problem that exists in conventional progressive press forming is that, during a pressing operation, metal can be pulled from one direction only. This arises from the fact that in a two-stage progressive forming operation for example, metal cannot be pulled back to the first stage whilst it is being worked-on in the second stage and/or it cannot be pulled into the second stage whilst it is subjected to a press forming operation in the first stage. Thus, all metal which is to be pulled into the first stage must be provided from the input side of the tool and all metal which is required to be pulled into the second stage must be provided from the output side of the tool. This restricts the shaping which ca be applied to the metal and/or requires that the shaping be created by stretch-forming the metal. The latter approach requires expensive tooling and high powered presses.
U.S. Pat. Nos. 2,510,024 and 2,954,068 and British patent specification No. 1,398,027 disclose press tools which operate in a manner such that metal is pulled into the tools from two directions during formation of longitudinally extending corrugations. However, the tools which are disclosed in the referenced patent specifications cannot be used to form articles which have intersecting form lines.